• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.9
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• pp.1-8
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• 1993

In this paper, a new approach to the minimization of two-level Reed-Muller circuits is presented. In contrast to the previous method of using Xlinking operations to join two cubes for minimization. Cube selection method tries to select cubes one at a time until they cover the ON-set of the given function. A simple heuristic for selecting appropriate cubes is presented. In this heuristic, simply all cubes from the largest to the smallest are tried and whenever they decrease the number of remaining terms they are accepted. Since cubes once selected are not considered for a new selection, our method takes less time than other methods that need repetitive optimization process. The experimental results turned out to be improved in many cases compared to the best results in the literature.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.363-365
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• 1991

This paper presents a method for feeder reconfiguration in order to operate distribution systems efficiently using heuristic rules. The reconfiguration method presented here not only eliminates various abnormal states but also achieves minimum power loss and optimum load balance of the distribution feeders under normal operating condition transfering loads from one feeder to anoter applying the experiences of the experts. To implement the method effectively, a best-first tree searching strategy based on heuristics is used to evaluate the various load transfer alternatives. The development of a rule-based system aimed at the reduction of the search space is presented as a means of implementing the best-first searching strategy. The results of the computer simulation of the above procedure are as follows; 1) achieving minimum power loss of the distribution feeder adopting the optimum load transfer alternative. 2) Enhencing system reliability and achieving load balance through rational allocation of the feeder loads.

• Journal of the Korean Operations Research and Management Science Society
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• v.19 no.3
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• pp.63-79
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• 1994

Many vehicle fleet planning systems have been suggested to minimize the routing distances of vehicles or reduce the transportation cost. But the more considerations the method takes, the higher complexites are involved in a large number of practical situations. The purpose of this paper is to vehicle fleet planning system. This paper is considered multi-objective optimization. The vehicle fleet planning system developed by this study involves such complicated and restricted conditions as one depot, multiple nodes (demand points), multiple vehicle types, multipel order items, and other many restrictions for operating vehicles. The proposed algorithm is compared with the nearest neighbor heuristic (NNH) and the savings heuristic (SAH) algorithm in terms of total logistics cost and driving time. This method constructs a route with a minimum number of vehicles for a given demand. This method can be used to any companys which vehicle fleet planning system under circumstances considered in this paper.

• Journal of Korean Institute of Industrial Engineers
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• v.30 no.2
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• pp.120-129
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• 2004

This paper provides a simple but effective method, cost relaxation to escape from a local optimum of the traveling salesman problem. We would find a better solution if we repeat a local search heuristic at a different initial solution. To find a different initial solution, we use the cost relaxation method relaxing the cost of arcs. We used the Lin-Kernighan algorithm as a local search heuristic. In experimental result, we tested large instances, 30 random instances and 34 real world instances. In real-world instances, we found average 0.17% better above the optimum solution than the Concorde known as the chained Lin-Kernighan. In clustered random instances, we found average 0.9% better above the optimum solution than the Concorde.

• Korean Management Science Review
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• v.5 no.1
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• pp.56-70
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• 1988

In this study, We reviewed the solution methods (for the heuristic and optimization method) for the single-item dynamic lot-sizing problem, and improved the efficiency (speed and optimality) of the conventional heuristic method by utilizing the inventory decomposition property. The iventory decomposition property decomposes the given original problem into several independent subproblems without violating the optimality conditions. Then we solve each decomposed subproblems by using the conventional heuristics such as LTC, LUC, Silver-Meal etc. For testing the efficiency of the proposed decomposition method, we adopted the data sets given in Kaimann, Berry and Silver-Meal. The computational results show that the suggested problem solving framework results in some promising effects on the computation time and the degree of optimality.

• Journal of the Korean Operations Research and Management Science Society
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• v.14 no.1
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• pp.80-87
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• 1989

Many Traditional Algebraic Analyses of preference and choice for a finite set of alternatives have been based on binary choices. They have assumed that the binary preference information given by a decision maker is transitive. However, there is considerable evidence that many relations that might occur as preference relations cannot be presented as transitive relations. To construct transitive binary comparisons from intransitive ones, we suggest the notion of superior set, which helps us to understand the structure of intransitive binary comparisons. We also provide a heuristic method to construct transitive binary comparisons. And some merits merits of the suggested method over the existing methods are also discussed.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.2
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• pp.38-49
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• 1997

In this paper, w describe partitioning large circuits into multiple chips on the programmable FPCB for rapid prototyping. FPCBs consists of areas for FPGAs for logic and interconnect components, and the routing topology among them are predetermined. In the partition problem for FPCBs, the number of wires ofr routing among chips is fixed, which is an additonal constraints to the conventional partition problem. In order to deal with such aconstraint properly we first define a new partition problem, so called the topologybased partition problem, and then propose a heuristic method. The heuristic method is based on the simulated annealing and clustering technique. The multi-level tree clustering technique is used to obtain faster and better prtition results. In the experimental results for several test circuits, the restrictions for FPCB were all satisfied and the needed execution time was about twice the modified K-way partition method for large circuits.

• Journal of the Korea Safety Management & Science
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• v.8 no.5
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• pp.139-150
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• 2006

The aim of this study is to establish an efficient distribution planning for a capacitated multi-stage supply chain. We assume that the demand information during planning horizon is given a deterministic form using a certain forecasting method. Under such a condition, we present a cost effective heuristic method for minimizing chain-wide supply chain inventory cost that is the sum of holding and backorder costs by using look-ahead technique. We cope with the capacity restriction constraints through look-ahead technique that considers not only the current demand information but also future demand information. To evaluate performance of the proposed heuristic method, we compared it with the extant research that utilizes echelon stock concept, under various supply chain settings.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.9
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• pp.1681-1688
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• 2009

This paper proposes a new fault restoration method which adopts the recloser as top agent to release the problems of the data concentration and fault processing delay of the existing DAS(distribution Automation System) under the ubiquitous distribution system. In proposed method, top agent collects the data based on the multi-casting communication with the tie switches of the interconnection point, and then selects a closed switch(tie switch) to transfer the sound outage load to other feeders based on the heuristic search strategy step by step until the load transfer work is finished. Here, a new heuristic rule is developed which can guarantee the relational load balancing and line loss from the collected voltage data. Finally, the several faults are simulated for typical multi-section and multi-interconnection distribution system to prove the effectiveness of the proposed strategy, in particular, for each simulation cases, the load balancing index and line loss index of the obtained solution from the proposed method is compared with those of all of feasible solutions.

• Journal of Korean Institute of Industrial Engineers
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• v.15 no.1
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• pp.31-39
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• 1989

The throughput of a production line can be improved by a proper layout of machines and also by meterial flow control between machines. This paper presents a heuristic method of determining machine layout in one-dimensional space to reduce travel distance of material transporters. The heuristic method is compared to an optimum solution method to measure its performance.